Many beverages are provided for commercial dispensing in the form of a flavoured liquid concentrate and a diluent such as water or a carbonated liquid with the components to be delivered under pressure in selected proportions for mixing at the dispensing spout or discharged separately into a vessel wherein the components are blended together.
In the case of coffee, particularly, traditionally it has been brewed for commercial consumption in facilities utilizing ground coffee deposited in filters through which selected quantities of heated or boiling water are slowly passed whereupon the brewed batches are stored in vessels or in urns to be dispensed from time to time upon demand.
Variations in the character and quality of the product are to be expected because of the handling involved including the measuring out of quantities by the operator and because of problems presented by storage. Further, if brewed coffee must be stored for long periods at elevated temperatures, it tends to lose its freshness and flavour.
Liquid coffee concentrates derived from large commercial brewing facilities have been available and such concentrates can be supplied in packaged units of specified weight or in bulk for reconstitution into a potable beverage by the addition of hot water, provided the concentrate is properly stored at low temperatures, through automatic dispensing equipment.
Many difficulties however have been encountered with such equipment particularly in obtaining a dispensed mixture which is consistently uniform in the proportions of solute to diluent.